Blower DoorThis is what a blower-door looks like. It is being used as part of an energy-audit to determine the performance of a building. The blower-door itself is placed inside an exterior door frame. It pressurizes or depressurizes a building at 50 Pascals pressure, based on the testing method. A meter provides a read-out of the air-leakage of the building. This tells us how “leaky” the building envelope is. We can also search for these leaks while the blower is running. Tracer gas can be used, but a simple lighter will often do the trick as well, as its flame will start to move or even get blown out once near an air-leak. More obvious leaks can usually be felt, as they create significant drafts.

Knowledge is everything. It is the foundation of a good building performance upgrade.

Once problem spots are  identified with the help of a blower-door test for example, the actual problem can be addressed properly. Follow-up testing can show the success of any improvement measure at the end of a project. Consider it a quality-control measure.


While the blower-door is running, a thermal imaging camera can be used to identify thermal properties and imperfections of the building envelope. In this picture a cold spot along the edge of a wall-to-roof connection can be seen. The pressure difference that a blower-door creates will emphasize these issues in areas where air-leakage is a contributor to the temperature difference.

Energy Audits can be compared to a visit to the doctor. You know something is not quite right and you are looking for clarification and answers. The doctor’s visit is your first step to getting answers and coming up with a strategy for healing. With buildings, energy audits are the equivalent to a doctor’s visit. They tell architects and contractors what’s not quite right and where areas of improvement are. Knowledge is key to success. Once the issues are identified, they can be dealt with and solved most efficiently and effectively.

Energy Audits can typically be ordered from your utility company. They are heavily subsidized, so you on make a small copay. If you are considering working with an architect or contract, please invite her/him to the audit—there is nothing quite as powerful as first-hand knowledge transfer. At the very least, ask your auditor for a written report and photos of any problem spots she/he identifies.

Kare11 did a feature on energy audits. Make sure to order the extended audit. This one includes thermography.

One Comment

  • Mike Rogers says:

    Good recommendations–there are a lot of simple things people can do. And there are deeper improvements the make homes more energy-efficient (and safer and more comfortable at the same time) . Regarding the home energy audit, it’s important to get the right audit–accurate and actionable and looking at the right things like duct leakage, air infiltration, and equipment efficiency and combustion safety and an analysis of utility bills. We also do an infrared scan. For a bit more background on audits and additional links to EPA and DOE, follow my post at

    Thanks and good luck!

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